Fracture fixing device

ABSTRACT

Orthopaedic fracture fixation is effected by use of a tube with a spring extending through the tube bore and held under tension by terminal means which secure the device relative to a bone. The device can lie across the surface of a bone to bridge a fracture in the manner of a staple by using terminal members in the form of pins, screws or the like, and the spring tension can then serve to assist reduction of the fracture. Alternatively, the device can pass through the bone with terminal members held against opposite parts of the bone surface. In this case, the device may be one of a set used in threaded or other connection with an additional intramedullary nail or bone plate. Various mechanisms can be used for the terminal connections.

United States Patent 1191 Attenborough Apr. 30, 1974 [5 FRACTURE FIXINGDEVICE I 2,985,168 5/1961 Jonas eta]. 128/92 [75] Inventor: ChristopherGeorge Attenborough,

winchelsea, England Pnmary Examiner-Richard A. Gaudet AssistantExaminer.l. Yasko [73] Assrgnee: National llesearch DevelopmentAttorney, A or Fi m Cushman, Darby &

Corporation, London, England Cushman [22] Filed: Aug. 3, 1972 [21] Appl.No.: 277,569 ABSCT Orthopaedic fracture fixation is effected by use of a[30] Foreign Application p i i Data tube with a spring extending throughthe tube bore A 19 1971 Great Britain 989/. and held under tension byterminal means which secure the device relative to a bone. The devicecan lie [52] U 5 Cl 7 128/92 B 128 /92 A across the surface of a bone tobridge a fracture in the [51] k A61f 5/04 manner of a staple by usingterminal members in the 58] Fie'ld R 92 BC form of pins, screws or thelike, and the spring tension l28/92 A 92 BA 83 can then serve to assistreduction of the fracture. Al-

I 32/2" tematively, the device can pass through the bone with i terminalmembers held against opposite parts of the 56] Refrences Cited bonesurface. In this case, the device may be one of a P NT set used inthreaded or other connection with an addi- UNITED STATES ATE s tionalintramedullary nail or bone plate. Various GOOdykOOl'HZ mechanisms canused for the terminal connections 1,869,726 8/1932 Youngren 128/922,497,626 2/1950 Persall 128/92 11 Claims, 5 Drawing Figures FRACTUREFIXING DEVICE This invention concerns fracture fixing devices and moreparticularly such devices for orthopaedic use in fixing bone fractures.

More generally the invention provides a fracture fixing devicecomprising a tube, an elongate spring member dimensioned to passlongitudinally into the bore of said tube, and terminal means forconnection to the ends of said spring member to extend laterallyrelative thereto and afford fixation for the device in connection with abone while holding said spring member under tension in said tube.

Development of the invention in fact commenced with one form thereofwhich is suited to use from outside a bone and which acts in a generallysimilar manner to a staple in that it can bridge a fracture in the boneand be secured to mutually fractured portions of the bone. The addedadvantage of the invention is that the spring is used in thisapplication of the invention to apply force acting to reduce thefracture.

More particularly in this first form of the invention, the terminalmeans each comprise a pin, screw or equivalent component which isdeployed laterally relative to the spring member longitudinal axis toact as the arms of a staple, and at least one end of the tube is slottedto receive the pin. In practice, the device is assembled with the pinsheld against the tube ends by the spring under tension, but withouteither pin received in a slot. The device can then be used to bridge afracture, which may already be partly reduced, by suitably fixing thepins. After this fixing, the tube can be rotated to seat the relevantpin or pins in an associated slot, whereat the spring tension acts toreduce the fracture, or enhance an existing reduction.

It will be appreciated that there need be only one slot at one end ofthe tube, but there can be slots at both ends and/or more than one slotat either end. Also, it

. may be desirable to notch the tube, at least at a slotted end, to forma seat for the respective pin and reduce the possibility of undesirablerotation of the pin into a slot during fixation or preliminary handlingof the device. Naturally such notching should not be such as to renderrotation of the tube relative to the pin too difficult when it is infact required.

Also, while terminal means involving simple pins will be useful for manypurposes, it may, as indicated above, be appropriate to provide otherforms of device.

' For example, bone screws passing through an apertured spring terminalmember which is itself received in a tube slot rather than the screw maybe preferable in some circumstances.

The tube will normally be rigid, but this is not essential since it willbe appreciated that the tube need only have sufficient longitudinalrigidity to maintain the terminal means at its ends against the springtension acting therebetween.

Further development of the invention has led to a second form thereofwhich may be closely similar to the first form, but'differs in that itwill be employed normally as an ancillary to secure or enhance thestability of primary device such as an intramedullary nail or a boneplate. In this case the device of the invention is used from within thebone in the place of a bone plate screw, say, where the bone is thin,porous or otherwise of too poor quality for adequate conventionalfixation, or in connection with an intramedullary nail, say,

where the medullary canal geometry is subject to too great a variationto rely on the conventional frictional stabilisation, as in the lowerthird of the femur.

In this form of the invention the terminal means can each comprise anapertured first terminal member connected with one end of the spring,and a second terminal member for disposition transverse to the springlongitudinal axis and connection to the first terminal member by a wireor other coupling member. In addition, the tube may be externallythreaded at least part way along its length, or otherwise adapted inassociation with the primary device for connection therewith.

For example, the tube may be externally threaded along a central portionfor screw connection with an intramedullary nail to extend laterallytherefrom through a bone. In this case the nail is stabilized byconnecting the first terminal members of the spring second terminalmembers of plate or button-like form located on the outer bone surface.Such connections can be made by wire passed through the aperture of thefirst terminal member and also through or round the second terminalmember, and then twisted; by passing the first terminal member throughthe second terminal member, and then passing a locking pin through theaperture of the former member; or in any other convenient manner.

It will be appreciated that this mode of securement is particularlyappropriate when the quality of the relevant bone is poor since theforces to which the securement is subjected are spread across the bonesurface.

In another example, the device of the element may be connected towardsone end thereof with a bone plate, in which case the bone plate canserve as part of the terminal means, i.e. the second terminal member,for

vone end of the spring.

In any event, the above and other possible variations within the moregeneral scope of the invention will be better appreciated followingconsideration of exemplary embodiments thereof as illustrated in theaccompanying drawings, in which:

FIG. 1 illustrates an embodiment of the invention in side elevation, I

FIG. 2 illustrates the embodiment of FIG. 1 in longitudinal section,

FIG. 3 illustrates a modification of the embodiment of FIGS. 1 and 2,

FIG. 4 diagrammatically illustrates another embodiment of the inventionin association with an intramedullary nail, and

FIG. 5 similarly illustrates a modification of the embodiment of FIG. 4in association with a bone plate.

The embodiment of FIGS. 1 and 2 comprises a rigid circular cylindricaltube 1, having at one end a pair of diametrically opposed notches 2 anda longitudinal slot 3 located at a circumferentially central positionbetween the notches. A helical spring 4 extends through pin alignedtherewith, and the spring is of such length relative to the tube thatthe spring must be extended under tension to achieve the illustrateddisposition of parts. After fixation in this disposition with the pinssecured in respectively different parts of a fractured bone and the tubebridging the fracture, rotation of the tube causes the notch-seated pinto pass into the slot 3 whereat the spring pulls the pins closertogether and so reduces the fracture. Naturally, the spring tension issufficiently high that, even when relaxed by the closing movement of thepins, the reduced tension is still useful.

In the modification illustrated by FIG. 3 for the above embodiment, theterminal means 5 is replaced by a two-part terminal comprising separatefirst and second members 8 and 10. The first member 8 is in the form ofan apertured plate 11 with a screw 12 extending from its edge in theplane of the plate, while the second member 10 is a bone screwdimensioned to pass through the aperture of the plate 11 with the screwhead seating in or against the plate.- The screw of the first memberconnects with one end of the spring as in the original embodiment, andthe plate engages radially across the relevant end of the tube, in thenotch or slot, to hold the spring under tension in similar manner to thepreviously proposed pin. Securement to the bone is, of course, effectedby the bone screw in place of the pm.

The further embodiment of FIG. 4 is similar to that of FIG. 3 andcorresponding reference numerals are used where appropriate. However,the terminal means for the spring differ in that the second member isnot a bone screw but a disc 12 having two apertures 13 therein towardsits center so that this member is, for practical purposes, like abutton. In fact the member in question is used like a button in that thetube of the device is passed laterally through a bored passage in abone, and the spring is tensioned between its ends by threading a wire wthrough the aperture of the first terminal component, passing the freeends of the wire through the respective apertures of the disc with thedisc located over the adjacent end of the bored passage, and thentightening and twisting the wire to secure the resultant terminalconnection. This mode of fixation is useful, as noted above, when therelevant bone is of poor quality for more conventional fixationtechniques and the wire securement can conveniently be effected by useof the apparatus described in copending Great Britain Patent ApplicationNo. 38988/71.

The device of FIG. 4, as so far described, can be used in its own rightfor fixing an oblique fracture since it will serve to hold the fracturedparts together in a lateral sense under the spring tension, whileresisting movement in the longitudinal sense of the bone by virtue ofthe rigidity of the tube around the spring. In this last connection, itis to be noted that the tube will not engage the second members of theterminal means, but there need be no significant movement between thesemembers and the main body of the device if the main body terminatesclosely adjacent the bone surface areas in which the bored passageemerges.

However, the situations in which the device of FIG.

4 may be used alone are more likely to be those in which use is normallymade of an elongate fracture fixing member, such as an intramedullarynail or a bone plate, to provide rigidity along the longitudinaldirection of the bone against lateral movement in a fracture.Accordingly, the device of FIG. 4 is shown in association with anintramedullary nail.

For this last purpose the nail, denoted at 14 is provided with aplurality of lateral threaded bores 15 which are spaced apart in uniformand parallel manner along the length of the nail, and each bore 15 canbe associated with the device so far described when provided with athreaded portion 16 around the central part of its tube. Briefly, toachieve this arrangement, the nail is located along the relevantmedullary canal, the bone is bored laterally to form passagescommunicating with the canal in locations corresponding to the bores ofthe nail, the tubes of the associated devices are passed into the boresin the bone for screw connection with the nail, and the devices aresecured by way of their springs and terminal means as described above.Naturally, not all of the bores of the nail need be necessarily used inassociation with the fixation devices, but a regular sequence of boresis provided in the nail to allow selection to suit differentcircumstances.

For completeness in FIG. 4, an associated jig 17 is shown whereby thelateral bores can be made in the bone to correspond with the bores inthe nail which are to be employed for fixation. This jig comprises aprimary elongate member 18 having a first end portion 20, formed with asequence of lateral bores 21 corresponding to those of the nail, and asecond end portion 22 extending from the first and formed with twospaced lateral bores 23 parallel to the bores 21. The bores 21 areextended on opposite sides of the portion 20 by tubular members 24, andat least one of the bores 21 nearer the free end of portion 20communicates with an orthogonal threaded bore 25 which receives a screw26. The jig comprises a secondary elongate member 27 similar to portion22 of the primary member in overall geometry and the provision of twolateral bores 28. The secondary member is connectable with the primarymember in parallel disposition by two tie rods 30 which pass at theiropposite ends through corresponding ones of the bores 23 and 28, the tierod ends being threaded for securement by nuts 31.

The secondary member 27 differs in the provision of a longitudinal bore32 therethrough and a pin 33 extending parallel thereto from the end ofthe secondary member nearer to the first end portion 20 of the primarymember. This bore and pin respectively cooperate with correspondinglydisposed stopped bores 34 and 35 in one end of the nail, the bore 34being threaded.

In use of this jig, an initial lateral bore is made in the bone tocommunicate with the medullary canal, and the nail is passed into thecanal, with the end of the nail having the stopped bores 34 and 35outermost relative to the entry point, until one of the innermostlateral bores of the nail is aligned with the initial bore in the bone.Then a rod 36 with a threaded end 37 is passed into the bone bore toscrew into the aligned bore of the nail, while the other end of the rod36 is passed into the corresponding bore 21 of the primary member 18.Additionally, the secondary member 27 is abutted against the outermostend of the nail with the pin 33 located in the stopped bore 35, thelongitudinal bore 32 of the secondary member is aligned with the stoppedbore 34 of the nail, and a screw 38 is passed through the bore 32 toengage bore 34. Then the primary and secondary members are connected bythe tie rods 30, and the rod 36 secured by the screw 26, the tie rodssecured by the nuts 31, and the secondary member secured with the nailby the screw 38, to provide a rigid ladder-like arrangement of the jigand nail. The bores 21 of the jig primary member are then fixed inalignment with the bores of the nail, and the former serve as guides fordrilling lateral bores in the bone to communicate with the nail andreceive fixation devices.

In addition to providing enhanced securement in the presence of poorbone, the fixation is enhanced, as noted earlier, for a nail used incanal regions which do not normally offer adequate frictionalengagement. The more particular nail form and associated fixationdevices of FIG. 4 have been developed with the last advantage in mindfor use in the lower third of the femur,

and the nail is shaped for accommodation in this region with access fromthe knee but without requiringthe otherwise necessary, but notnecessarily successful, use of a nail of such length as to extend alonga major part of the femur. Also it will be appreciated that the jig canbe connected with the nail from either side.

The difficulty of fixation in poor bone is more likely to becomeapparent in connection with bone plates, which are normally fixed withscrews, and FIG. 5 illustrates a modification of the fixation device ofFIG. 4 in association with such a plate. The principal modification ofthe device is the provision of external threading 40 at one end of thetube of the device, rather than the center, for screw connection withthreaded bores 41 in a bone plate 42. Also, while the terminal means forthe fixation device spring can be as shown in FIG. 4, differentlymodified means are shown at the two ends of the device in FIG. 5 tofurther illustrate the possibility of variation within the more generalscope of the invention.

At the end of the device for connection with the bone plate, theterminal means comprise a first member 8 of apertured plate form as inFIG. 3, while the bone plate serves as the second member. Moreparticularly, the aperture of the bone plate has a radial slotextension43 through which the first member plate can pass and be locked byrotation in the manner of a turn-buckle.

At the other end, the device again employs a terminal device comprisinga first member 8 of apertured plate form, but instead of associationwith a doubleapertured button for connection by wire, the second membercomprises a disc 44 with a slot 45 through which the member 8 can passto be locked by a pin 46 threaded through its aperture.

Clearly, both ends of the tube of the fixation device of FIG. 5 can bethreaded for association with respective bone plates on opposite sidesof the bone. Also, it will be apparent that screw connection of thefixation device and plate is not essential, since the plate can simplyserve as an integrated second terminal means member for a plurality offixation devices.

While the invention has been more particularly described with referenceto a number of specific embodiments thereof, it has been made very clearthat it is susceptible to wide variation in its superficially simpleform. These variations will suit different practical applications inorthopaedic fracture fixing, but exhibit a common characteristic ofproviding tension by way of a spring extending between fixation points,while the spring is stiffened laterally by an encompassing tube.

I claim:

1. An orthopaedic fracture fixing device comprising a tube, an elongatespring member located under tension along the bore of said tube, and apair of terminal means connected with respective ends of said springmember, said terminal means extending externally of the tube laterallyrelative to the longitudinal direction of said tube across the ends ofthe tube for securing said spring member relative to a bone and holdingsaid spring member, under tension, against relaxation into said tube.

2. A device according to claim 1 wherein said terminal means eachcomprise a pin adapted for fixation in said bone by penetrationthereinto, which component is deployed laterally relative said springmember, and said tube is slotted in a longitudinal sense from at leastone end thereof to slidably receive said component.

3. A device according to claim I wherein said terminal means eachcomprise a discrete first terminal member connected with the respectiveend of said spring member, and a discrete second terminal member,separably interconnected with said first terminal member.

4. A device according to claim 3 wherein said first terminal member isof apertured form, and said second terminal member is formed with twoapertures, and said terminal means each further comprise a length ofwire of which an intermediate portion passes through said first terminalmember, and the free end portions of said wire pass respectively throughsaid two apertures, to connect said terminal members by twisting saidwire free end portions.

5. A device according to claim 3 wherein each of said first and secondterminal members is of apertured form, the aperture of said secondterminal member receiving the apertured part of said first terminalmember therethrough, and each of said terminal means further comprisinga locking pin passing through said apertured part.

6. A device according to claim 3 wherein said second terminal member isof apertured form, and said first terminal member is passed at leastpartly through said second terminal member and thereafter rotated aboutsaid longitudinal direction to extend across said second terminalmember.

7. A device according to claim 3 wherein the external surface of saidtube is threaded at least part way along the length thereof; anadditional fracture fixing member internally threaded for screwconnection with said threaded external surface.

8. A fracture fixing assembly comprising a plurality of devicesaccording to claim 3 in each of which the respective tube is externallythreaded over an intermediate portion thereof, and an elongateintramedullary member having a plurality of threaded lateral borestherethrough individually receiving said devices in screw connection.

9. A fracture fixing assembly comprising a plurality of devicesaccording to claim 3 and at least one elongate bone plate constitutingsaid second terminal in common for one set of corresponding ends of saiddevices.

10. A fracture fixing assembly comprising a plurality of devicesaccording to claim 7 in each of which said threading extends over an endportion of the respective tube, and an elongate bone plate having aplurality of threaded lateral bores therethrough to individually receivesaid devices in screw connection.

11. An orthopaedic fracture fixing device, comprising:

a rigid tube having a longitudinal bore;

a coil spring received in and extending along said bore;

a first terminal means extending laterally externally of the tubeadjacent one end of the tube;

first means connecting one end of the spring to said first terminalmeans;

a second terminal means extending laterally exter- 10 nally of the tubeadjacent the other end of the tube;

ranged to not interdigitate until the tube is rotated about itslongitudinal axis to a predetermined disposition relative to the secondterminal means whereupon the tension on said spring means pulls theprotrusion and recess means into interdigitation, thus moving the secondterminal means toward the first terminal means;

the length of the spring relative to the tube being such that the springremains tensioned when said protrusion and recess means areinterdigitated;

whereby the first and second terminal means may be connected to a boneon opposite sides of a fracture thereof with the protrusion and recessmeans not interdigitated, and the tube rotated relative to the secondterminal means to interdigitate the protrusion and recess means, thuspermitting the spring to shorten, drawing the first and second terminalmeans together and thus reducing the fracture.

1. An orthopaedic fracture fixing device comprising a tube, an elongatespring member located under tension along the bore of said tube, and apair of terminal means connected with respective ends of said springmember, said terminal means extending externally of the tube laterallyrelative to the longitudinal direction of said tube across the ends ofthe tube for securing said spring member relative to a bone and holdingsaid spring member, under tension, against relaxation into said tube. 2.A device according to claim 1 wherein said terminal means each comprisea pin adapted for fixation in said bone by penetration thereinto, whichcomponent is deployed laterally relative said spring member, and saidtube is slotted in a longitudinal sense from at least one end thereof toslidably receive said component.
 3. A device according to claim 1wherein said terminal means each comprise a discrete first terminalmember connected with the respective end of said spring member, and adiscrete second terminal member, separably interconnected with saidfirst terminal member.
 4. A device according to claim 3 wherein saidfirst terminal member is of apertured form, and said second terminalmember is formed with two apertures, and said terminal means eachfurther comprise a length of wire of which an intermediate portionpasses through said first terminal member, and the free end portions ofsaid wire pass respectively through said two apertures, to connect saidtErminal members by twisting said wire free end portions.
 5. A deviceaccording to claim 3 wherein each of said first and second terminalmembers is of apertured form, the aperture of said second terminalmember receiving the apertured part of said first terminal membertherethrough, and each of said terminal means further comprising alocking pin passing through said apertured part.
 6. A device accordingto claim 3 wherein said second terminal member is of apertured form, andsaid first terminal member is passed at least partly through said secondterminal member and thereafter rotated about said longitudinal directionto extend across said second terminal member.
 7. A device according toclaim 3 wherein the external surface of said tube is threaded at leastpart way along the length thereof; an additional fracture fixing memberinternally threaded for screw connection with said threaded externalsurface.
 8. A fracture fixing assembly comprising a plurality of devicesaccording to claim 3 in each of which the respective tube is externallythreaded over an intermediate portion thereof, and an elongateintramedullary member having a plurality of threaded lateral borestherethrough individually receiving said devices in screw connection. 9.A fracture fixing assembly comprising a plurality of devices accordingto claim 3 and at least one elongate bone plate constituting said secondterminal in common for one set of corresponding ends of said devices.10. A fracture fixing assembly comprising a plurality of devicesaccording to claim 7 in each of which said threading extends over an endportion of the respective tube, and an elongate bone plate having aplurality of threaded lateral bores therethrough to individually receivesaid devices in screw connection.
 11. An orthopaedic fracture fixingdevice, comprising: a rigid tube having a longitudinal bore; a coilspring received in and extending along said bore; a first terminal meansextending laterally externally of the tube adjacent one end of the tube;first means connecting one end of the spring to said first terminalmeans; a second terminal means extending laterally externally of thetube adjacent the other end of the tube; second means connecting theother end of the spring to the second terminal means, the length of thespring relative to the tube being such that the second terminal means ispulled against the other end of the tube by the spring and maintains thespring in tension; interdigitable protrusion and recess means on saidsecond terminal means and said tube other end, arranged to notinterdigitate until the tube is rotated about its longitudinal axis to apredetermined disposition relative to the second terminal meanswhereupon the tension on said spring means pulls the protrusion andrecess means into interdigitation, thus moving the second terminal meanstoward the first terminal means; the length of the spring relative tothe tube being such that the spring remains tensioned when saidprotrusion and recess means are interdigitated; whereby the first andsecond terminal means may be connected to a bone on opposite sides of afracture thereof with the protrusion and recess means notinterdigitated, and the tube rotated relative to the second terminalmeans to interdigitate the protrusion and recess means, thus permittingthe spring to shorten, drawing the first and second terminal meanstogether and thus reducing the fracture.